2.0 TDI 170 CBBB Engine. Smoking on exhaust / turbo?

[Woodburner]

I have a 74,000 mile 2.0 TDI 170 Quattro A3 Sportback. Car has been dealer serviced (it was my old company car) and has never missed a beat. Recently though I've noticed a hot oil / fuel smell when the car has been used. I popped the bonnet and noticed some smoke / fumes coming from the rear of the engine bay where the exhaust is. I have indicated on the attached photo where the smoke is coming from. What is this component? Any thoughts? I've checked the oil and coolant levels and all is fine although from time to time the fan stays on a long time after the engine is switched off, suggesting it is getting very hot even though the temp gauge reads normal. I'm hoping it's not a turbo oil seal on its way out.

 

[Retroman]

Sounds and looks like the DPF. The car carries on running the fan if the engine is stopped during an "activated regeneration". Burning smells during this process is also commonplace.